Cathode line connector system



June 8,1948. J. H. NYE 2,442,778

CATHODE LINE CONNE QTOR SYSTEM Filed Jan. 51, 1944 ifai lnrll."

INVENTOR. J/IMES H. NY;

Warm;

A TTOFAEY Patented June 8, 1948 GATHODE LINE CONNECTOR. SYSTEMi J ames. Henry. Nye, Jackson, Heights, N. Y., assignor to Federal Telephone and. Bodiofiorporation, New York, N. Y., a corporationof Delaware.

Application January 31, 1944,;SerialNo. 520,571.

9-Claims. I;

This invention; relates .to resonant line oscillators wherein the-dual conductors are shielded and employ means for tuning the lines to the desired frequency.

Heretofore, one of the means. of tuningtransmission line circuits coupled to line sections mounted-within a closed,envelope (for example for. tuning cathode filaments) was to place a short circuiting bar across the two conductors of; the transmission line and slide the bar toward or away fromthe envelope until the desired frequency has been reached This is generally at approximately a quarter wavelength from the endop theline section. This type of shorting meanshas been found to be eflicient for ordinary frequencies where a quarter wavelength of the frequency. is a considerable distance from the end of; the-line section to the shorting bar. In vacuum tubesoperating at ultra high frequencies the distance from the internal end of. the filament becomes considerably shortened so that the length of the cathode filament may approach a quarter wavelength in itself. With the types of couplings now in use, it is quite diflicult to brin the shorting bar to within a quarter wavelength ofthe end .of the cathode filament, therefore, an oddmultiple of a quarter wavelength must be employed. 'Thisis undesirable as it lengthens the. structureto a, prohibitive degree.

Oneofthe objects of my invention is to provide. means whereby an effective short circuit for tuning a partially enclosed line section to resonance maybe made substantially at the point at, which the line section extends from the envelope.

Another object of my invention is to provide means whereby the tuning short circuit for a vacuum tube filament line may be broughtinto close, proximity to the tube, whereby tuning of the filament line to an ultra high frequency at which the filament and internal leads are substantially a quarter wavelength long can be attained.

A. further object of my invention is to provide means whereby a tube may be readily connected toand disconnected from the shielded resonant ne.

Further and ancillary objects of my invention will become apparent in the following description and Y drawings, wherein:

Fig. 1 is a front elevational view partly in sect DI of ayacuum tube coupled to a shielded resonantjine oscillator and-embodying the priniples o y nven on;

Fig.2 is a horizontal sectionalview takenalong the lines 22 of Fig. 1';

Fi 313 apartial. v rtica c i nal 'view' e n alon the nes.3l. .ofi 1; a d

Fig. 4 isa schematic diagram of the electrical c uit emg oyed'inr a Z'an 3- Referrineto. Figal. the e s u t at :a va uum tube. l,. of.'the type employing: the' usual cathode}, grid '3 .andjanode 4; wherein the cathode 2; of thistube is provided with a filament 2a, apair of. filament leads .5 and: figforming atwo conductor line element within the tube-and a thirdorneutral'lead11' Ail three-*otthese'leads extend. throu h. and beyond the envelopeand are sealedheaii their remote ends. The-central or neutrallead'l is secured-to the lowerend of the cathode filament and is employed both-as-a centering, rod. and 5 ground connection: The remote endsof these three leads ,5, ,5- and! extending beyond. the. sealin meansoftthe tube'proiect into the. adjacent end: of the oscillator:-

Eachoi these cathode leads; are provided with flangedslip bushings 8; 9311111 H1; held-in-frictional engagementthereto by-slottedcylindrical portions Ba, Sdand Ilia, and having fiangedbases 8b, 9b and 10b of a greater diameter than-the cylindricallportions and adaptedto rest upon the leadsealing. means of the envelope of tube I. A two-conductor shielded line 38" having shielded conductors 20' and 2| is-connectedto the tube I. Secured to the ends of each oithe shielded conductors .20 and 2|, by soldering or brazing, are cylindrical couplings 2-2 and; 23'- ada-pted-to be slipped upon and surround-the bushingsii and'9 and secured in placeagainst'any accidental longitudinal movement by the set screws 24..and'25. Secured to the inner periphery-of the shield 39, and insulated therefrom by-a'thin-sheet of mica, are a pair of contact springs- 31 and '32, the bifurcated ends of which-surround the cylindrical'portions 8a and 9a and also bear down with a definite amount ofpressureupon the upper surface of the flanges 8b and-- 9b;to not .only assist in holding the bushings against the .lead sealing beads of the tube, but to assure. the proper amount of electrical contact. The. other; ends of said springs are bent at right angles .tothe bifurcations and are secured tothe shield by screws-33 and-34 and, in eifect, act as the condensers C in the radio frequency shorting circuit. Although the condensersC offer-:an .in-finiteimpedanceto-the direct current being. fed-to the cathode filament, they offer a negligible.,-impedance to'the radiofrequency, thereby effecting a tuning short circuit -ac1oss.- the -,conductor dines 20; 2| 7 Preferably, there isalsopro ided anothen-contact spring 35, similar to. .those already i ifi bfi 3 V and more clearly shown in Figs. 2 and 3, the upturned end of which is fastened directly to the inner periphery of the shield by a screw 36, the bifurcated end bearing upon the upper surface of the flange llib of the slip bushing and surrounding in part the cylindrical portion Illa. Thi spring 35,'however, is not insulated from the shield but makes a direct electrical connection to ground through the shield.

It can readily be seen that with this construcinto the openings 31 and 38 in theshield- 30 to It will be apparent from the foregoing description that an effective short circuiting of the 7 radio frequency is provided by by-passing the radio frequency from the conductors 20 and 2| to ground through the springs 3| and 32, the condensers C, and shielding 30, without causing any plied to the filament of the cathode 2. It will also be apparent that with this type of construction the short circuiting means can be brought to the extended ends of the filament at their juncture with the envelope, thus tuning the cathode to resonance at a frequency at which the cathode is substantially a quarter wavelength long. With this construction it has been found possible to tune an oscillator using a tube usually suitable for operation. only at lower frequencies to operate at approximately 700 megacycles per second.

While I have disclosed my invention applied to vacuum tube filament tuning, it should be understood that it is not limited to this particular use. The principles of my invention apply to any circuit in which it is desired externally to tune a line substantially enclosed in any envelope to the highest radio frequency at which it can operate.

It will be clearly understood by those skilled in the art, that the apparatus shown and described herein is only illustrative of my invention and is not to be construed as a limitation on the scope of my invention as set forth in the objects and appended claims.

I claim: 7

1. A line connector system connecting a vacuum tube comprising an envelope and a two conductor line element having a pair of leads extending through and beyond said envelope to a two'conductor shielded line, comprising means 1 coupling together said leads and the conductors of said shielded line, conductive means conductively connected to respective leads externally of .said envelope substantially at the point where circuit at the operating radio frequency is pro- ;adjust the set screws 24 and 25, thereby c'onnecting or disconnecting the dual line conductors .from the tube.

4 7 means comprising connectors connected to said leads substantially at the point where said filament leads emerge from said vacuum tube envelope and positioned adjacent to portions of the shield of said line, and means insulating said connectors from said shield, said connectors, said insulating means and said adjacent shield portions forming low impedance radio frequency condensers whereby an effective short circuit at 10 tion it is only necessary to insert a screw driver the operating radio frequency is provided across said filament leads.

3. A. cathode line connector system according l to claim 8, further comprising a third cathode filament lead extending through and beyond the seal of said envelope, a slip bushing having slotted cylindrical portions and a flanged base of greater diameter than the cylindrical portion,

interference to the heating current being ,sup-

vided across said leads to tune said line element.

2. A cathode line connector system having means for tuning a cathode filament to a high radio frequency comprising a vacuum tube envelope, a, cathode filament in said envelope having a pair of filament leads extending through and beyond said envelope, a two conductor shielded line, means coupling together said cathode filament leads and the conductors of said two- (of said shielded conductor line, said condenser said bushing being positioned upon said third.

filament lead, a contact spring bifurcated at one end bent at right angles to the bifurcation at the other, fastened directly to the inner periphery of the shield of said shielded conductor line thereby connecting the filament directly to ground.

4. 'A cathode line connector system adapted for. use with ultra high frequency circuits and including means for tuning a cathode filament to an operating frequency at which the filament is substantially a quarter wavelength,,said means comprising a vacuum tube envelope, a cathode filament having three filament leads mounted within and extending through and beyond said envelope to supply heating energy to said filament, a two-conductor shielded line, means coupling together said cathode leads and the two conductors of said shielded line and the shield substantially at a point where said filament leads emerge from said envelope contact means conmeeting said leads to the shield of said line, the ends of said contact means adjacent said shield being mechanically connected to said shield, and

.means insulating at least one of said contact n the contact means for said midpoint connected lead is conductively connected to said shield.

r 6. A line connector system for connecting a vacuum tube comprising an envelope and a two conductor line element having a pair of leads extending through and beyond said envelope to a two conductor shielded line, comprising slip bushings each provided with a slotted cylindrical portion and having a flanged base of greater diameter than the cylindrical portion, positioned uponeach of said leads, a cylindrical coupling joined to eachof the conductors of the shielded line adjacent said slip bushings, means on said coupling whereby each of said couplings and its associated slip bushing and lead may be secured together, and condenser means coupled between respective leads externally of said envelope and the shield of said shielded conductor line substantially at the point where said leads emerge line element.

'7. Aline connector system for connecting a vacuum tube comprising. an envelope and a twoconductor line element having a pair of leads extending through and beyond saidenvelope to a two-conductor shielded line, comprising slip bushings, each provided with a slotted cylindrical portion and having a flanged base of greater diameter than the cylindrical portion, positioned upon and conductively connected to each of said leads, a cylindrical coupling conductively joined to each of the conductors of the shielded line adjacent said slip bushings and conductively connected to said slip bushings, and condenser means coupled between respective leads external of said envelope and the shield of said shielded conductor line substantially at the pointwhere said leads emerge from said vacuum tube envelope whereby an effective short circuit at the operating radio frequency is provided across said leads to tune said line element.

8. A cathode line connector system having means for tuning a cathode filament to a high radio frequency comprising a vacuum tube envelope, a cathode filament in said envelope having a pair of filament leads extending through and beyond said envelope, a two-conductor shielded line, means coupling together said cathode filament leads and the conductors of said two-conductor line, and condenser means coupled between respective leads of said filament and the shield of said shielded conductor line substantially at the point Where said filament leads emerge from said vacuum tube envelope, said condenser means comprising a contact spring bifurcated at one end and bent at right angles to the bi-furcation at the other, insulated from and fastened to the shield of said shielded conductor line and adapted to pass radio frequency current to ground, whereby an effective short circuit at the operating radio frequency is provided across said filament leads.

9. An electron tube system comprising an electron tube having an envelope, electrodes within said envelope and electrode leads extending through said envelope, a line comprising at least two conductors and forming with at least two of said leads a resonant circuit, and connectors connecting said conductors to said leads substantially at the point at which the leads emerge from said envelope, at least one of said connectors comprising conductive means conductively connected to one of said leads substantially at the point Where it emerges from said envelope and positioned adjacent to a portion of the conductor connected to another of said leads and means insulating said conductive means from said last mentioned conductor, said conductive means, said insulating means and said conductor portion forming a condenser having a low impedance at the operating frequency of the system.

JAMES HENRY NYE.

REFERENCES CITED The following references are of record in the 

